【C语言】将两个字符串连接起来

#include<stdio.h>
int main()
{
    char s1[] = "I ";
    char s2[] = "am a student";
    int i, j, n;
    for (i = ; s1[i] != '\0'; i++)
        ;
    n = i;
    for (j = ; s2[j] != '\0'; j++)
    {
        s1[n] = s2[j];
        n = n + ;
    }
    s1[n] = '\0';
    printf("%s", s1);
 
}